"This is not the right time for bullet train in the country but there was a need for improving existing facilities, speed, infrastructure and comforts of passengers," Sreedharan, also known as the 'Metro Man' for developing the vibrant Delhi Metro, said in an informal interaction with reporters on sidelines of a function here.

He said the Railways should concentrate on betterment of the existing facilities at the outset and think of bullet train later.

"May be after eight to 10 years, we may require bullet train," Sreedharan said.

To a query on the proposed bullet train between Mumbai and Ahmedabad, Sreedharan, who had spent about 36 years with Railways, expressed his satisfaction over the progress of the Nagpur Metro Rail project.

The Nagpur metro project, he said, was using a new technology where the via duct will be of 8.5 metres against the 10 metres in other Metro Rails across the country.

Earlier, at the first foundation day programme of Nagpur Metro Rail, Sreedharan said the project should be completed on time and it should be affordable to the users, since it was a public transport.

"If you don't complete the project within the time frame, the cost will escalate Rs 50 lakhs per day. When the detailed Project Report of Delhi Metro was drafted, the completion target was given 10 years but we finished in seven years and three months, which was a record, thereby saving a huge revenue," he said.

Educate the public and users about the utility and engage them so that there are no inordinate delays in execution, he said, emphasising on evolving a work culture among employees and staff to inculcate a 'sense of integrity'.

Citing example of Delhi, he said a run of 65 kms Metro Rail reduced congestion on road traffic as about 35,000 cars were off roads and Rs 3 lakh crore was saved on fossil fuel.